This invention relates to an assembly of labels removably adhered in spaced apart relation to the release surface of a carrier web which may be a plastic film but is usually a smooth dense paper coated with a silicone release layer. The labels comprise a pressure-sensitive adhesive in contact with the surface of the release layer and a label base layer, and may include contrasting indicia in one or more colors printed over the label base layer. Labels are sold without indicia, for example ring binder reinforcement rings, patching labels, shipping labels, name tags and the like. Indicia are often employed however and can comprise printed letters, graphics, decorative foils, grain patterns, or the like. Such labels, with or without printed indicia, are referred to as "laid-on" labels and are in wide commercial use for attachment to various articles and materials for purposes of identification, provision of operating characteristics and instructions, hazard warnings, decoration, advertising, protection and repair.
Laid-on labels are presently made by die-cutting which is described, for example, in U.S. Pat. Nos. 2,391,539 and 3,166,186. A sheet or roll of base laminate of coextensive layers comprising the label base, the pressure-sensitive adhesive, and the temporary carrier web having a release surface in contact with the adhesive, is fed through a press. The indicia, if any, are printed and the desired periphery of the individual labels is provided by die-cutting through the overlying layers, but not the carrier web. The surplus material, between labels, is then stripped from the carrier web as a skeleton and is discarded. Protective overcoatings can be applied to the labels before or after stripping of the skeleton.
The base laminate is usually made by coating a carrier web, for example glassine paper, with a liquid silicone resin solution, followed by drying and curing (polymerizing) the silicone resin. A liquid pressure-sensitive adhesive composition, either a molten hot-melt or solvent solution, is then coated over the silicone surface and converted to a plastic solid. The label base layer, for example a printing paper, plastic film, foil or the like, is then laminated to the adhesive. Such base laminates are usually made on large coaters in wide widths and slit into rolls or cut into sheets of sizes suitable for particular press operations.
Die-cutting of labels as described above results in a substantial waste of skeleton materials removed between labels, which can amount to as much as half the starting material. Moreover, provision and operation of the dies, and their maintenance, represents added expense and difficulty. Also, pressure applied in die-cutting the periphery of the labels, or in handling the finished labels, can cause the plastic pressure-sensitive adhesive to ooze beyond the periphery of the label and cause blocking in storage and difficulty in feeding and dispensing the labels. The large coaters and ovens employed are expensive and require relatively large volumes of product for economical operation. Also, high temperatures can damage or limit the selection of the materials employed.